Tire conditioning apparatus

ABSTRACT

Tire conditioning apparatus is provided for removing flat spots and other surface irregularities from tires preliminary to recapping or truing them. The apparatus comprises a frame, drive rolls mounted in the bottom of the frame for supporting and rotating the tire, pressure assembly arranged to press the tire against the drive rolls with a predetermined amount of pressure, and heating means located a spaced distance from the tire for heating it as it is rotated under pressure. This removes the stresses and permits the tire to assume its normal shape.

d States Patent Hall et a1.

[451 Jan. 1, 1972 TIRE CONDITIONING APPARATUS Walter Dennis Hall;Malcolm Jean Charles, both of Lodi, Calif.

Assignee: Super Mold Corporation Filed: Dec. 3, 1969 Appl. No.: 881,841

Inventors:

11.8. C1 ..425/ll, 157/13, 264/36, 264/94, 425/170, 425/367, 425/446Int. Cl. ..B29h 3/00, B29h 21/00 Field ofSearch ..18/1R,D1G.41; 157/13;264/36, 94; 144/288 References Cited UNITED STATES PATENTS 8/1953Anderson et a1 ..157/13 X 6/1968 Hughes ..264/36 3,480,068 1 H19693,495,296 2/1970 Ericson et a1. 3,529,048 9/1970 Kovac et a1... ..264/94Primary ExaminerRobert L. Spicer, Jr. Attorney-Eugene D. Farley [57]ABSTRACT Tire conditioning apparatus is provided for removing flat spotsand other surface irregularities from tires preliminary to recapping ortruing them. The apparatus comprises a frame, drive rolls mounted in thebottom of the frame for supporting and rotating the tire, pressureassembly arranged to press the tire against the drive rolls with apredetermined amount of pressure, and heating means located a spaceddistance from the tire for heating it as it is rotated under pressure.This removes the stresses and permits the tire to assume its normalshape.

9 Claims, 3 Drawing Figures PATENTEDJANWQYZ 3.635610 Eigfl. Fig 2.

Walfer Dennis Hal] Malcolm decm Chan 6S BY INVENTORS TIRE CONDITIONINGAPPARATUS This invention relates to tire conditioning apparatus. ltpertains particularly to apparatus for returning tires to their normalshape and condition preliminary to recapping them and truing them.

Under certain conditions, pneumatic tires develop stresses whichappreciably deform them.

ln the manufacture of new tires, varying rates of cure applied afterinitial curing in the mold induces tresses that are gradually relievedover a period of several months use of the tire.

In use, tires are subject to a condition known as Nylon Set. This is theresult of stresses set up in the tire by the weight of the vehicle whenthe latter is at rest.

Similar stresses are induced in tires stored in stacks or random piles,by the weight of the superimposed tires pressing against the tires atthe bottom.

The inevitable result of these various stress-producing conditions is todeform the tire, causing irregularities and flat spots. The presence ofsuch irregularities is of the greatest importance when recapping ortruing the tire. if a low spot is present in the tire about to berecapped, it is not eliminated by the steps of buffing and treadbuilding. it appears as a high spot after the tire is put to use.

When truing a tire, high spots must be removed prior to the balancingoperation. This normally is accomplished by trimming off the excessrubber. However, if the excess rubber is in the form of a lump or highspot caused by displacement of the rubber, grinding off the excessuniformly about the periphery of the tire obviously will removeunnecessarily a great deal of useful tread.

Accordingly it is the general purpose of the present invention toprovide apparatus for conditioning tires preliminary to recapping andtruing them.

It is another purpose of the present invention to provide such apparatuswhich will accomplish its desired function rapidly and universally ontires of various sizes, weights and condition.

It is still a further object of the present invention to provide tireconditioning apparatus which, although it rotates the tire at a highrate of speed is of relatively simple construction, easily controlled,and free of vibration.

Still a further object of the invention is the provision of tireconditioning apparatus involving the application to the tire of heat andpressure under carefully controlled and coordinated conditions.

The manner in which the foregoing and other objects of this inventionare accomplished will be apparent from the accompanying specificationand claims considered together with the drawings, wherein:

FIG. 1 is a view in side elevation, and

FIG. 2 in front elevation of the presently described tire conditioningapparatus, both views being partly broken away to reveal interiorconstruction; and

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1.

The tire conditioning apparatus of this invention is housed in anexterior frame which to advantage may assume the configuration of acabinet sized to receive the tire edgewise in an upright position.

The frame thus includes a bottom 10, a pair of sidewalls l2, 14, abackwall 16, a partial front wall 18, and a top 20. Sidewalls l2 and 14with partial front wall 18 define an opening or doorway through whichthe tire is introduced into the interior of the apparatus.

Within the apparatus are appropriately disposed means for driving thetire at a high rotational speed, for guiding it, for applying flexingpressure to it, and for heating it while it is being flexed, togetherwith means for controlling the degree of pressure and heat applicationat the optimum levels.

To this end there are mounted on floor of the unit a pair of spaceddrive rolls 22. Each of these is fixed to a shaft 24 which is joumaledin bearings 26 secured to the opposite sidewalls of the frame.

Preferably, drive rolls 22 assume the configuration of a pair offrustoconical members arranged base to base. This provides a centralridge and outwardly tapered peripheral areas which have an importantfunction. As the flexed tire rotates rapidly on the rolls, it iscentered automatically by the peaked or ridged configuration of thelatter so that vibration and wandering of the tire are minimized, oreven completely eliminated.

Drive rolls 22 are spaced from each other a sufficient distance tosupport a tire upright, on edge, in a freely rotatably position. Bothrolls are driven synchronously by a drive which includes electric motor30, belt 32 engaging a pulley on the shaft 24 of one of drive rolls 22,and a belt 34 interconnecting pulleys on the shafts 24 of both of driverolls 22. The drive thus provided rotates the tire rapidly, for exampleat speeds equivalent to 20 miles per hour.

Guide means are provided for guiding the tire as it rapidly rotates,insuring that the tire remains upright and centrally oriented within theframe.

In the illustrated form of the invention the guide means comprise threepairs of guide rolls 38, 40, 42. These are journaled in arms mounted onthe respective sidewalls of the frame. They are disposed radially withrespect to the tire and are arranged at suitable angles to each other,for example, in an angular relationship of where there are three guideroll pairs. However, more or fewer of the guide roll pairs may beemployed if desirable or necessary.

As the tire rotates on the drive rolls, it is pressed by a pressure rollassembly which has for its function flexing the tire and kneading it,thereby assisting in returning it to its original undeformed condition.

The pressure roll assembly employed for this purpose includes a pair ofparallel arms 46. The inner ends of the arms are pivotally mounted onbrackets 43. The outer ends of the arms support between them acrosspiece 50. A pressure roll 52 is joumaled in bearings supported bythe cross piece. This important member of the apparatus may be made ofany hard, durable material, preferably smooth-surfaced steel.

Drive means are provided for reciprocating the press roll 52 between aretracted position, wherein it is out of engagement with the tire, andan advanced position where it engages the same, these being thefull-line and dotted-line positions, respectively, of FIG. 1.

In the illustrated form of the invention, the drive means em ployed forthis purpose comprise a pair of fluid-operated cylinders, preferablypneumatic cylinders 54. The cylinders are single acting, being driven inthe advancing or downward direction.

The case of each cylinder is bolted to a bracket 56 suspended from thetop 20 of the frame. The piston rod of the cylinder pivotally engages acrossbar 58 which extends between arms 46.

Retraction of pressure roll 52 is accomplished through the agency of acoil spring 60 which interconnects a frame member such as bracket 56 andan extension of crosspiece 50.

Accordingly pressure roll 52 may be advanced into pressure contact withthe periphery of the tire by the advancement of the piston rod ofcylinder 54. It is maintained in this position as long as pressureapplication to the tire is desired. Then upon release of the drive ofthe cylinder, spring 60 returns the pressure roll to its retractedstation.

Heating means are included in the apparatus for the purpose of softeningthe rubber tire to make it more susceptible to the kneading action ofpressure roll 52.

To this end an open frame 62 is supported on arms 46. Frame 62 mounts aplurality of electric heating elements 64 which are supplied withelectric current through a lead wire 66.

It is to be noted that frame 62 is spaced slightly from arms 46, in thedirection away from the tire. The purpose of this arrangement is tospace the heating element an optimum distance from the tire when thepressure roll is in its operative position, thus insuring that the tireis heated sufficiently to be rendered somewhat plastic without beingoverheated.

In the operation of the device, a tire is loaded through the frontopening onto drive rolls 22. Drive motor 30 is started. This rotates thetire at a predetermined rotational speed.

Electric heating elements 64 are activated and cylinder 54 advanced toplace pressure roll 52 in contact with the peripheral surface of thetire.

The heating elements soften the rubber while the pressure roll kneads itas required to work out any flat spots or surface irregularities. Thedesired result is achieved rapidly, an operating cycle of from 4 to 5minutes usually being sufficient.

It is evident that tires of various size, condition and composition varymaterially in the resistance they offer to pressure roll 52. Sufficientpressure must be applied by this roll to work the rubber. Accordingly,it is desirable to provide means for adjusting the pressure of the rollto correspond to the resistance offered by the tire.

This problem is solved in the present invention by taking advantage ofthe fact that the power requirements of the drive motor 30 also arerelated to the tire characteristics. Accordingly, by placing an ammeterin series circuit relation with the motor, the drive motor amperage maybe utilized as a measure of the rolling resistance of the particulartire which is in the machine. The load on the pressure roll is thenadjusted so that the motor develops a constant maximum ammeter reading,which is the optimum pressure value.

Thus in the front partial panel 18 of the frame, there may be provided agroup of instruments which appropriately accomplish these functions. 70Indicates an on-off cycling switch which initiates the automatic cycle.It starts drive motor 30, energizes heating element 64 and advancescylinder 54. 72 Indicates an ammeter which is in series circuit relationwith the drive motor. 74 Indicates a valve control for controlling thefluid pressure exerted by cylinder 54.

Accordingly, after initiating the cycle of operation by pushing button70, the operator watches ammeter 72 and adjusts air pressure regulatorvalve 74 until the desired ammeter reading is obtained. The unit thenruns automatically until the cycle is completed.

Having thus described my invention in preferred embodiments, I claim asnew and desire to protect by letters patent:

1. Tire conditioning apparatus comprising:

a. an exterior frame dimensioned to receive a tire edgewise,

b. drive roll means mounted across the bottom of the frame forsupporting the tire in an upright, freely rotatable position and forrotating the tire at a predetermined rotational speed, c. pressure rollmeans mounted on the frame above the tire, d. pressure roll drive meansconnected to the pressure roll for reciprocating it between an advancedoperating posi- 5 tion where it exerts a predetermined pressure againstthe tire, pressing it against the drive rolls and a retracted loadingposition remote from the tire, and

e. tire heating means positioned for heating the tire to a predeterminedtemperature as it rotates under pressure.

2. The tire conditioning apparatus of claim 1 including tire guide meansmounted along the sidewalls of the frame for maintaining the tire in anupright position as it rotates.

3. The tire conditioning apparatus of claim 1 wherein the drive rollmeans includes a pair of spaced drive rolls, each having a central,annular ridge and outwardly tapered peripheral surfaces forself-centering the tire as it rotates thereon.

4. The tire conditioning apparatus of claim 1 wherein the pressure rollmeans comprises a pair of arms extending from the rear wall of the framein the direction of the tire, pivotal mounting means mounting the outerend of the arms to the rear wall, and a pressure roll joumaled betweenthe inner ends of the arms.

5. The apparatus of claim 4 wherein the tire heating means is mounted onthe arms a spaced distance therefrom in the direction away from thetire, thereby spacing the heating means from the tire when the pressureroll is in contact with the same.

6. The apparatus of claim 4 wherein the pressure roll drive meanscomprises a double -actin fluid-o rated cylinder.

7. The apparatus of claim 4 w erem t e pressure roll dnve meanscomprises a single-acting, fluid-operated cylinder operative to drivethe pressure roll means to its advanced position against the tire, andspring means coupled to the pressure roll means for returning thepressure roll means to its retracted position upon inactivation of thecylinder.

8. The apparatus of claim 1 wherein the tire heating means compriseselectric heating means and an electric circuit including the same.

9. The tire conditioning apparatus of claim 1 wherein the drive rollmeans comprises at least one drive roll coupled to an electric motor inan electric circuit with an ammeter and the pressure roll drive meansincludes control means for adjusting the pressure developed thereby, thecontrol means being adjustable to adjust the pressure to an optimumlevel indicated by the ammeter reading.

1. Tire conditioning apparatus comprising: a. an exterior framedimensioned to receive a tire edgewise, b. drive roll means mountedacross the bottom of the frame for supporting the tire in an upright,freely rotatable position and for rotating the tire at a predeterminedrotational speed, c. pressure roll means mounted on the frame above thetire, d. pressure roll drive mEans connected to the pressure roll forreciprocating it between an advanced operating position where it exertsa predetermined pressure against the tire, pressing it against the driverolls and a retracted loading position remote from the tire, and e. tireheating means positioned for heating the tire to a predeterminedtemperature as it rotates under pressure.
 2. The tire conditioningapparatus of claim 1 including tire guide means mounted along thesidewalls of the frame for maintaining the tire in an upright positionas it rotates.
 3. The tire conditioning apparatus of claim 1 wherein thedrive roll means includes a pair of spaced drive rolls, each having acentral, annular ridge and outwardly tapered peripheral surfaces forself-centering the tire as it rotates thereon.
 4. The tire conditioningapparatus of claim 1 wherein the pressure roll means comprises a pair ofarms extending from the rear wall of the frame in the direction of thetire, pivotal mounting means mounting the outer end of the arms to therear wall, and a pressure roll journaled between the inner ends of thearms.
 5. The apparatus of claim 4 wherein the tire heating means ismounted on the arms a spaced distance therefrom in the direction awayfrom the tire, thereby spacing the heating means from the tire when thepressure roll is in contact with the same.
 6. The apparatus of claim 4wherein the pressure roll drive means comprises a double-acting,fluid-operated cylinder.
 7. The apparatus of claim 4 wherein thepressure roll drive means comprises a single-acting, fluid-operatedcylinder operative to drive the pressure roll means to its advancedposition against the tire, and spring means coupled to the pressure rollmeans for returning the pressure roll means to its retracted positionupon inactivation of the cylinder.
 8. The apparatus of claim 1 whereinthe tire heating means comprises electric heating means and an electriccircuit including the same.
 9. The tire conditioning apparatus of claim1 wherein the drive roll means comprises at least one drive roll coupledto an electric motor in an electric circuit with an ammeter and thepressure roll drive means includes control means for adjusting thepressure developed thereby, the control means being adjustable to adjustthe pressure to an optimum level indicated by the ammeter reading.